1. Technical Field
The present disclosure relates to an analog to digital converter. More particularly, the present disclosure relates to a dual-mode analog to digital converter.
2. Description of Related Art
Analog to digital converters are commonly used in a variety of electronic products, such as signal input interfaces of displays, sound cards, etc. With different applications of analog to digital converters in various products, parameters such as resolution, operating frequency, dynamic range, etc. of the analog to digital converters usually determine performance of the products.
Different types of analog-to-digital conversion technologies have been rapidly developed in recent years. One common analog to digital converter is developed based on sigma delta modulation technology. In this type of analog to digital converter, noise shaping and over-sampling technologies are employed to allow the analog to digital converter to have a high resolution. Thus, the analog to digital converters based on the technology using a sigma delta modulator are frequently applied to biomedicine or processing of high order images/voices.
Another common analog to digital converter is a successive approximation analog to digital converter. This type of analog to digital converter redistributes the capacitive charges repeatedly so as to generate the digit code correspondingly. However, owing to the impact of process variation, mismatches among capacitors usually occur in successive approximation analog to digital converters so that resolutions of this kind of analog to digital converter are not easily increased.
Generally speaking, the above-mentioned two types of analog to digital converters are implemented with different circuit architectures, and the different circuit architectures are required depending on the service condition in advance and are not allowed to be changed based on different input signals flexibly. For example, when the frequency of the input signal is low, a sigma delta analog to digital converter may be utilized to improve the overall resolution. When the overall power consumption and rate are considered, a successive approximation analog to digital converter may be utilized.